The operator's compartment of most commercial vehicles, such as the cockpit of an airplane, generally includes at least one control panel. The control panel includes a plurality of switches that are in communication with a variety of electrical or hydraulic systems. In a typical system, actuation of the switch produces a relatively low current output to activate the switching action of a larger driver circuit. Such driver circuits are used to actuate a variety of systems, such as the landing gear or running lights of the vehicle.
Switches currently available for such systems include both contact and contactless switches. Contact switches include gold-plated leaf springs that may be actuated into and out of physical contact with the driver circuit. Typically, these switches include a tactile response to indicate when the switch changes state.
Contactless switches generally include a magnet and a sensor that is sensitive to magnetic forces to produce electronic control pulses. In a typical contactless switch, the magnets are permanently mounted to a device that is either rotated or linearly translated into close proximity with the sensors to change the state of the switch. In contactless switches having linear translation of magnets, the switch may also include a separate tactile mechanism. The tactile mechanism is coupled to the translation of the magnets to produce a tactile response while changing the state of the switch. A tactile response is desirable because it allows the operator to confirm actuation of the particular system without requiring visual confirmation. Although both contact and contactless switches are effective at changing the state of a switch, they are not without problems.
Relative to contact switches, because physical contact between the switch leaf springs and circuit is required to close the circuit, such switches often suffer high rates of failure. Additionally, debris or corrosion may build up between the switch leaf springs and circuit, thereby causing an unintended and undesirable increase in the impedance of the switch. Contactless switches tend to be expensive because they require a separate tactile mechanism coupled to the switch actuation to produce the anticipated tactile response. Further, due to the tactile mechanism, such contactless switches have additional parts and, therefore, they are not only difficult to manufacture, but also have a greater chance of failure.
Thus, there exists a need for a contactless switch that not only produces an anticipated tactile response, but is also economical to manufacture, has a high degree of reliability and meets the performance expectations of the end user.